Transfer an image of a Western woman in flagrante from a mobile phone to the internet and it's little more than a social embarrassment. But when the same thing happens in Chennai (Madras), as it does in Anupama Chandrasekhar's Free Outgoing, the result verges on the cataclysmic. India may be technologically progressive, but morally it's often as conservative as it was 50 or 100 years ago; or so Indhu Rubasingham's pacy, robust production suggests.

This isn't a very subtle play, but it packs quite a punch as what begins as a family problem escalates into a national scandal. Brainy young Deepa, who has been caught having sex with a boy in a classroom, never appears onstage and so we're presumably expected to imagine her emotions and opinions after she's first suspended, then expelled from her school and left to fester in her bedroom. But the feelings of her widowed mother, Lolita Chakrabarti's Malini, are almost too clear.

The actress is all disbelief when Deepa's headmistress comes to break the bad news, ominously warning her that the girl's status is now the traditional one of slut, and she's successively defensive, furious, baffled, desperate and despairing as things deteriorate. Malini starts by breaking, binning or confiscating anything Western, from movie mags to the TV, and ends up preparing to move house as neighbours in her Tamil community reject the family, stones break windows, a crowd gathers and television arrives with cameras and the sort of smug interviewer one thought was native to Britain and America.

Thanks to her acting as well as her pole position in the plot, Chakrabarti makes a strong impression, never more so than when she sits, broken and ashen, before the TV lights. Likewise Amit Shah as Deepa's distressed, angry brother, whose hoped-for career as an engineer is imperilled by her disgrace.

But I never fully understood the relevance of Raj Ghatak's Ramesh, who is one of Malini's work colleagues and a near-permanent fixture on stage. Perhaps it's simply to suggest that, though he purports to be helpful, he actually suffers from the male chauvinism and prurience that's destroying Deepa. But I'm not sure he adds a lot to a play that's always worthy, and sometimes more, but not as provocative in England as it surely would be if it were staged in that fascinating amalgam of the 21st and 19th centuries, modern India.

Box office: 0207-565 5000

Editor's choice

• Burning Bush with W
• Greatest movie partnerships
• Nicole Kidman returns to Australia